Core Summary
When selecting a hydraulic cylinder, one should not solely consider the cylinder diameter and working pressure. The standards themselves dictate the installation interface, interchangeability, and pressure capacity limit. It is advisable to first align the operating conditions (pressure level, stroke, medium), and then decide whether to use a rod-type, wafer flange-type, or heavy-duty cylinder, which can reduce subsequent modifications and downtime. Conforti covers both ISO 6020/2 and ISO 6022 standard series, facilitating the continuation or upgrade based on the original equipment interface.
1. Standards come first, ensuring stable interfaces
ISO 6020/2 and ISO 6022 are two commonly used standards for square cylinders
ISO 6020/2 covers a working pressure rating of 160 bar, while ISO 6022 is designed for heavy-duty applications up to 250 bar. Many equipment modifications fail not because of incorrect cylinder bore calculations, but because the old cylinder has been installed with flanges and hole positions according to a certain standard, while the new cylinder, despite having similar external dimensions, cannot match the interface. Specifying "which standard to follow" in the procurement requirements is essential for suppliers to provide a direct replacement solution.
Switching between standards of the same brand is more hassle-free
When a production line includes both standard actuators and heavy-duty main cylinders, opting for cross-standard supply from the same brand simplifies spare parts management, seal inventory, and after-sales communication. Conforti's series, such as CD/DK/MD, HD/HK, and DP, fall under different standards but share unified interface information, facilitating overall coordination.
II. Whether it's a pull rod or a flange, it depends on the travel distance
The pull-rod structure is clear and easy to assemble and disassemble
The rod-type (CD/DK/MD) utilizes four rods to tension the end cap and cylinder barrel, featuring an intuitive structure and convenient maintenance, making it suitable for medium-range travel and general automation. With a working pressure of 160 bar and a cylinder diameter ranging from 25 to 200 mm, it is a widely used general-purpose model.
For long-distance travel, avoid stretching the pull rod
After the stroke is extended, the rod is stretched during pressure maintaining and reciprocating, leading to a decrease in the rigidity of the cylinder body, and the end tends to shake or creep. For the flange clamp type (HD/HK), the rod is removed and replaced with a flange on the outside of the cylinder barrel for direct clamping, resulting in better overall rigidity. The working pressure is increased to 210 bar, suitable for long strokes exceeding 2000 mm. When retrofitting certain types of hydraulic presses, replacing the rod cylinder with a flange cylinder alleviates the shaking issue during long strokes.
III. High-pressure heavy-duty walking cylinder
250 bar graded bronze guide
In applications with high loads such as injection molding and presses, a 250 bar DP heavy-duty cylinder equipped with bronze guide bushes exhibits more stable wear resistance and pressure maintenance performance. When selecting the model, inform the supplier of the peak pressure rather than the typical pressure to avoid selecting based on average values, which can lead to insufficient margin and pressure drop during the pressure maintaining phase.
Seals are selected based on the medium
The same cylinder can be equipped with different sealing solutions to accommodate hydraulic oil, water-glycol, or special media. Clearly state the type of medium and temperature range, as selecting the wrong seal can lead to leakage within a few months, requiring downtime for seal replacement.
4. For position feedback, use a servo cylinder
Built-in sensors eliminate the need for external wiring
Real-time knowledge of piston position is required (such as closed-loop pressing and multi-cylinder synchronous lifting), utilizing servo cylinders (TD/TK/TH/TX/TP) equipped with built-in magnetostrictive position sensors. These sensors rely on magnetic field positioning without physical contact, offering superior accuracy and lifespan compared to external wire displacement meters, while also eliminating the need for external wiring and protective casings.
Select series by pressure rating
Servo cylinders are also categorized by pressure ratings: TD/TK for 160 bar, TH/TX for 210 bar, and TP for 250 bar. First, determine the circuit pressure, and then select the cylinder bore within the corresponding series to avoid using a low-pressure series in high-pressure applications.
V. Procurement Checklist
Operating pressure (including peak values) and required standards (ISO 6020/2 or ISO 6022)
Stroke length, determine whether it exceeds the applicable range of the pull rod type
The installation method and interface hole positions should adhere to the original standards as much as possible
Medium type, temperature range, and sealing solution
Is position feedback (servo cylinder) or corrosion-resistant surface (nickel plating) required
Spare parts and delivery schedules, long-tail models should be confirmed for inventory in advance
Parameter Table (Series Comparison)
> The above is a selection guideline. Specific parameters are subject to the original Conforti documentation. QN TECHNOLOGY provides model selection verification for series such as CD/DK/MD, HD/HK, and DP. We welcome you to send us your operating condition parameters for comparison.
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